Conventionally, in particular, in the field of the clinical examination, a known measurement instrument includes a measurement instrument for reacting a specimen such as human blood, urine, etc., with a reagent, and measuring, for example, the change of the absorbance of the reagent, thereby determining a specific component in the specimen.
As such a conventional measurement instrument, an instrument using a disposable reagent is known. The disposable reagent can be classified into a cartridge type reagent in which a liquid reagent is filled in a container (hereinafter, “a reagent cartridge” will be referred to) and a test piece, that is, a so-called dry reagent.
The test piece is allowed to carry a reagent by impregnating a filter paper or sheet resin, etc., or by forming a reagent layer on a base material. Before reacting with a specimen, the test piece is in a dry state or in a substantially dry state (at least not in a liquid state). That's why the test piece is referred to as a dry reagent.
On the other hand, the reagent cartridge, which has a plurality of chambers into which necessary reagents, etc. are dispensed in accordance with items to be measured, is supplied in a state in which it is sealed by measurement instrument makers, reagent makers, etc. At the time of measurement, when a specimen is filled in a specimen chamber of the reagent cartridge and then the reagent cartridge is set in the measurement instrument, the measurement instrument, for example, automatically mixes the specimen with the reagent, and carries out the measurement.
A conventional measurement instrument corrects the reagent sensitivity before measurement by taking the deterioration of a reagent over time and a difference of a reagent between lots into account. That is, every time a user of the measurement instrument purchases a new lot of reagent cartridge or test piece, the user carries out the work including measuring a material having a known concentration by using the purchased reagent cartridge or the test piece, thereby forming a calibration curve for each lot of the reagent cartridge or the test piece, and storing it in the instrument.
In general, the user carries out a measurement of two kinds of materials, that is, a high concentration standard liquid and a low concentration standard liquid, forms a calibration curve as a linear expression by connecting both measurement values, and stores the formed calibration curve in a recording medium such as a magnetic card that can be read by the measurement instrument. This work takes a lot of time and labor. Therefore, in many cases, makers of a reagent cartridge or test piece manufacture a recording medium in which information of a calibration curve is stored for each lot and ship the above-mentioned recording medium together with the reagent cartridge or the test piece by attaching it on the reagent cartridge or the test piece.
However, as mentioned above, since the conventional measurement instrument carries out the linear expression correction by a calibration curve, there have been problems in that it is difficult to carry out an adequate correction in accordance with the difference between lots of a reagent, and that in the case where the reagent sensitivity in accordance with the deterioration over time changes non-linearly, an adequate correction cannot be carried out.